Nattokinase

Natto Enzyme · Bacillus subtilis natto · Subtilisin NAT

Snapshot

Indications	Contraindications
Blood pressure support¹ Stroke rehabilitation adjunct² Lipids with red yeast rice^{3, 4} Thrombosis prevention⁵	Soy allergy⁶ Anticoagulant therapy⁵ Bleeding disorders⁶ Pregnancy or breastfeeding⁶

Nattokinase is an enzyme produced when Bacillus subtilis ferments soybeans into natto, and it is taken as a supplement for its fibrinolytic activity⁵. That effect on clot breakdown drives its use for blood pressure, thrombosis prevention, and stroke rehabilitation, and alongside red yeast rice for lipids.

A meta-analysis of randomized trials found lower systolic and diastolic blood pressure, while lipid findings were mixed¹. A multi-year trial in older adults at low cardiovascular risk found no effect on carotid atherosclerosis progression⁷. In hypercholesterolemic adults, supplementation prolonged clotting measures⁸. In a 2026 narrative review of treatments for long-term symptoms after coronavirus disease 2019 (COVID-19), nattokinase was prioritised by clinicians and patients, yet it had no trial in that condition⁹. About 641 products listing nattokinase are marketed, and the sampled products are all capsules; see Form comparison.

The most consequential caution is bleeding, because the enzyme's fibrinolytic activity can compound anticoagulant effects; case reports describe fatal bleeding and valve thrombosis after warfarin was replaced with it⁵. Health Canada labels ask for a practitioner's advice before use with cardiovascular, kidney, or liver disorders or any medication⁶.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

40 sources, 23 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources